AC/DC phone line detector

ABSTRACT

An example AC/DC phone line detection system may include one or more of an electronic circuit that is floating with reference to ground, a first A/D converter coupled to the electronic circuit and configured to detect ringing voltages from DC voltages included in a telephone line, a second A/D converter coupled to the electronic circuit and configured to detect caller identification information from AC voltages included in the telephone line, and a processor configured to control signals detected by the first and second A/D convertors and output information about the signals to call taking equipment.

TECHNICAL FIELD

This application generally relates to a microcontroller for monitoring atelephone line, and more particularly, to a system and method which candetect information from AC and DC voltage of a telephone line whilemaintaining a high enough common mode rejection for all orders ofharmonics of a standard harmonic frequency (e.g., 60 Hz, etc.)

BACKGROUND

Electrical systems and communication cabling systems including emergencycall taking systems including 911, E911, public-safety-access points(PSAPs), nurse/hospital equipment, and the like, require grounding ofthe equipment in order to satisfy safety standards (e.g., ULrequirements, etc.) Electrical cabling communication systems that arerequired to be grounded must be connected to the earth. The groundingmechanism must provide a reliable means to safely conduct voltages whichcan be interrupted or rapidly affected by other sources such aslightning, line surges, unintentional contact with high voltage lines orequipment to ground, and the like. By effectively groundingtelecommunication equipment, the equipment and the phone service can beprotected, personal safety can be ensured when workers and others areexposed to the equipment, system performance can be ensured, and thelike.

In emergency call taking equipment, there is also a requirement todetect and decode caller ID information from the phone line. Unlikenon-emergency equipment which is completely floating and present alongitudinal balance to the telephone line, emergency equipment that isgrounded can struggle to generate enough common mode rejection ratio. Insome environments, the phone line may include common mode (e.g., 60 Hzcommon mode). In these situations, a portion of the 60 Hz harmonics,which can be up to or more than 4000 Hz, can be translated asdifferential mode signals that prevent the emergency call takingequipment from properly detecting caller ID information.

SUMMARY

In one example embodiment, provided is an AC/DC telephone line detectionsystem that may include one or more of an electronic circuit that isfloating with reference to ground, a first A/D converter coupled to theelectronic circuit and configured to detect ringing voltages from DCvoltages included in a telephone line, a second A/D converter coupled tothe electronic circuit and configured to detect caller identificationinformation from AC voltages included in the telephone line, and aprocessor configured to control signals detected by the first and secondA/D converters and output information about the signals to call takingequipment.

In another example embodiment, provided is a telephone system that mayinclude one or more of call taking equipment including a display, and amicrocontroller configured to detect caller identification (ID)information from a telephone line being input to the telephone systemand output the detected caller ID information to the display, whereinthe microcontroller may include an electronic circuit that is floatingwith reference to ground, a first A/D converter coupled to theelectronic circuit and configured to detect ringing voltages from DCvoltages included in a telephone line, a second A/D converter coupled tothe electronic circuit and configured to detect caller identificationinformation from AC voltages included in the telephone line, and aprocessor configured to control signals detected by the first and secondA/D converters and output information about the signals to the calltaking equipment.

In another example embodiment, provided is a method that may include oneor more of receiving a telephone signal via a telephone line betweencall taking equipment and a central office, the telephone signalcomprising alternating current (AC) and direct current (DC) voltages,detecting, via a first analog-to-digital (A/D) converter, ringingvoltages from DC voltages included in the telephone signal, detecting,via a second A/D converter, caller identification information from ACvoltages included in the telephone signal, and controlling, via aprocessor, signals detected by the first and second A/D converters andoutputting information about the signals to the call taking equipment,wherein the first A/D converter, the second A/D converter, and theprocessor, are electronically connected to each other and coupled to anelectronic circuit that is floating with reference to ground.

Other features and modifications may be apparent from the followingdescription when taken in conjunction with the drawings and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a proper understanding of the examples described herein, referenceshould be made to the enclosed figures. It should be appreciated thatthe figures depict only some embodiments and are not limiting of thescope of the present disclosure.

FIG. 1 is a diagram illustrating a telephone communication network inaccordance with an example embodiment.

FIG. 2 is a diagram illustrating a microcontroller for detecting AC andDC signals from a phone line in accordance with an example embodiment.

FIG. 3 is a diagram illustrating a method for detecting AC and DCsignals from a telephone line in accordance with an example embodiment.

FIG. 4 is a diagram illustrating a computing system in accordance withan example embodiment.

DETAILED DESCRIPTION

It will be readily understood that the components of the presentapplication, as generally described and illustrated in the figuresherein, may be arranged and designed in a wide variety of differentconfigurations. Thus, the following detailed description of theembodiments of at least one of a method, apparatus, non-transitorycomputer readable medium and system, as represented in the attachedfigures, is not intended to limit the scope of the application asclaimed, but is merely representative of selected embodiments.

The features, structures, or characteristics as described throughoutthis specification may be combined in any suitable manner throughout theembodiments. In addition, the usage of the phrases such as “exampleembodiments”, “some embodiments”, or other similar language, throughoutthis specification is used to indicate that a particular feature,structure, or characteristic described in connection with the embodimentmay be included in the at least one embodiment and is not to beconstrued as being omitted from other embodiments. Thus, appearances ofthe phrases “example embodiments”, “in some embodiments”, “in otherembodiments”, or other similar language, may be used to refer to thesame group of embodiments, and the described features, structures, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

In addition, while the term “message” may be used in the description ofembodiments, the application may be applied to many types of networkdata, such as, packet, frame, datagram, etc. The term “message” or“request” may include packet, frame, datagram, and any equivalentsthereof. Furthermore, while certain types of messages and signalingrequests may be depicted in example embodiments they are not limited toa certain type of message, and the application is not limited to acertain type of signaling.

The instant application relates to a microcontroller circuit that maymonitor and detect call information from alternating current (AC) anddirect current (DC) voltages included in a telephone signal. Themicrocontroller circuit can be embedded within, coupled to, or otherwiseconnected to a telephone system such as an emergency call takingposition which is connected to ground. Emergency call taking systemsincluding 911, E911, public-safety-access points (PSAPs), nurse/hospitalequipment, and the like, require grounding of the equipment in order tosatisfy safety standards (e.g., UL requirements, etc.) According tovarious aspects, the microcontroller includes an electronic circuitboard that is floating with reference to ground. That is, the electroniccircuit board may include a voltage that is not connected by anyconducting path (including resistors) to ground or that is otherwisefloating with respect to ground. In this case, the call taking positionmay be grounded but the microcontroller may not be connected to earth oranother circuit that is grounded.

The microcontroller may include a plurality of analog-to-digital (A/D)converters that are configured to detect different signals fromdifferent portions of an incoming telephone signal. For example, themicrocontroller may include a first A/D converter that detects ringingvoltages from a DC voltage included in the telephone line and a secondA/D converter that detects caller identification information from ACvoltages included in the telephone line. The microcontroller may alsoinclude a power source that can maintain a voltage in isolation betweenthe telephone line and the call taking equipment to withstand surges.According to various aspects, the microcontroller circuit may generate ahigh common mode rejection ratio such that caller ID information can bedetected regardless of the harmonics of the telephone signal.

A telephone line consists of two wires which are referred to as tip andring that transport a differential signal, meaning a signal that is ofopposite phase on each wire. When a signal increases on one wire, itdecreases on the other wire. Telephone equipment is designed to operatewith differential signals. A common mode signal is a signal that has thesame phase on both wires. When one wire signal increases, the signal onthe other wire increases proportionally. Telephone equipment is notdesigned to work with common mode signals and is actually disturbed byit.

Common mode signals, mainly 60 Hz and its spectral components, arecaused by a telephone cable running along power lines in telephone polesfor miles. The two cables run in proximity to each other for miles whichcauses the telephone to “pick up” some 60 Hz signal along the way. This60 Hz signal is picked up equally by both wires in the telephone line,creating common mode on the line. 60 Hz common mode is undesirable on atelephone because it can create a loud distinctive “hum” noise that iscontinually present. If the Common Mode Rejection Ratio (CMRR) of thetelephone equipment is high, the 60 Hz signal and is spectral components(multiples of 60 Hz that can be present with the 60 Hz, such as 120 Hz,180 Hz, up to 3600 Hz) will be eliminated and the caller or call takerwill not hear the unwanted noise. If the CMRR is not high enough, aportion of the common mode noise is converted into differential noiseand becomes audible on the telephone equipment. Usually, the higher thefrequency the lower the CMRR of the equipment. This can create noisycalls where it is almost impossible to hear the caller during anemergency call or the caller can be heard over the noise, but somedetails of the environment of the caller that could be critical to theproper response of the call taker can be lost into the noise.

The example embodiments describe a microcontroller that incorporatesmultiple A/D converters. The signals from the analog input circuits arefed to the inputs of the two A/D converters. All of the outputs of theA/D converters on the micro controller are then multiplexed onto a TimeDivision Multiplexed (TDM) bus that is then transmitted, through a 1500Visolation barrier, to the ARM processor (CPU) of the product. Bothconverters have their own connection to the telephone line. The highvoltage converter has a direct connection to the line, thereforedetecting both AC and DC voltages. The low level converter has an ACcoupled connection to the line, meaning that it only detects the ACvoltages and filters out the DC voltage. This allows the high levelconverter to detect both the ringing voltage and the DC battery whilethe low level converter only needs to detect the voice and caller IDsignals. The microcontroller removes common mode from the line incomparison to related call taking equipment.

Ideally, it would be preferable to have only one converter that woulddetect all the signals. Unfortunately, this is not practical because thehigh level signals need to be attenuated to be measured properly by alow level circuitry while the low level AC signals need to be amplifiedto be measured properly. Accordingly, the microcontroller of the exampleembodiments has two different similar converters, but having twodifferent analog inputs, one that is an attenuator and the other that isDC blocking and has a gain.

FIG. 1 illustrates a telephone communication network 100 in accordancewith an example embodiment. As an example, the telephone network 100 maybe include a telecommunications network used for connecting andmaintaining telephone calls between two or more parties. Examples of atype of network that may be included in the telephone network 100include a landline network where the telephones are directly wired intoa telephone exchange (also referred to as a public switched telephonenetwork or PSTN), a wireless network in which telephones are mobile andcan move around anywhere within the coverage area, a private networkwhere a closed group of telephones are connected primarily to each otherand use a gateway to reach the outside world which is referred to as aprivate branch exchange (PBX), an Integrated Services Digital Network(ISDN), and the like.

A telephone call represented by a telephone signal travelling throughthe telephone network 100 may carry voice transmission from a telephone,data transmission (e.g., when the calling party and called party areusing modems), facsimile transmission (e.g., fax machines), and thelike. The call may use a land line, a mobile phone, a satellite phone,any combination thereof, and the like. The telephone line may refer to adirect connection to a telephone line outside of a building, alsoreferred to as an “analog line”, or “POTS line” (Plain Old TelephoneService), in other words a standard residence type phone line. The POTSline is the line you will need for your remote broadcast console,telephone hybrid, analog telephone, cordless telephone, fax machine, ormodem. The telephone line may include two wires called tip and ring.These two wires may provide DC current to power the telephoneelectronics, AC current to ring the telephone bell or electronic ringer,and a full duplex balanced voice path.

The signal on a tip/ring pair may be full duplex, balancedbi-directional audio. This design allows signals to travel for mileswithout expensive shielding by using common mode rejection to removenoise that is induced onto both wires. In order to send and receiveaudio through the pair, the network 100 may include a two wire to fourwire hybrid circuit which converts the pair into separate transmit andreceive audio paths. Bulky and expensive hybrid transformers have beenreplaced in most telephones by integrated circuits which perform thesame function. Whether it is a transformer or IC, the hybrid shouldprovide at least 1500 volt isolation and surge suppression fromlightning strikes to satisfy standards/requirements. For example, ULstands for Underwriter's Laboratory. It is an American safety consultingand certification company. The UL requirements include 60950-1. This isa standard that specifies requirements intended to reduce risks of fire,electric shock or injury for the user who may come into contact with theequipment. This standard has been harmonized almost worldwide. Iflightning strikes a telephone cable or if a telephone cable is subjectedto a power cross (a 2 kV to 35 kV electrical distribution cable falls orsomehow touches a telephone cable), a surge voltage of up to 1500V canbe present on the telephone equipment. A 1500V isolation guarantees thatthe equipment connected to the line will not be damaged or a person onthe phone at that moment will not be hurt by the voltage surge.

In the example of FIG. 1, a calling system 110 is connected to areceiving system 150 via a communication network 130 which may includetelephone, mobile, satellite, and the like. As an example, the receivingsystem 150 may be an emergency call taking position that includes orconsists of a public-safety answering point (PSAP), however, thereceiving system 150 may include a non-emergency call system as well. Inthe example of the emergency all talking station, the receiving system150 may include a phone, a computing system, network connectivity, adisplay, and the like, and may connect to telephone and Internetnetworks. The receiving system 150 may include a dispatch applicationfor dispatching emergency responders, a computer animated design (CAD)system and/or a geographical information system (GIS) for generatingmaps and geographical information about the caller, a call takingapplication, and the like. An operator may interact with the receivingsystem 150 via a headset, a telephone, a screen, and/or the like.

FIG. 1 also includes multiple central offices 120 and 140 which are usedto connect the calling system 110 and the receiving system 150. Thecentral offices 120 and 140 may be part of a telephone exchange used ina public switched telephone network or in large enterprises. An exchangeconsists of electronic components that interconnect (switch) telephonesubscriber lines or virtual circuits of digital systems to establishtelephone calls between subscribers. As an example, a central office maybe defined as a building used to house the inside plant equipment ofpotentially several telephone exchanges, each serving a certaingeographical area which may also be referred to as the exchange.

In operation, the calling system 110 may place a call to the receivingsystem 150 via the interconnections generated and/or established by thecentral offices 120 and 140 and the network 130. According to variousaspects, the receiving system 150 may include a microcontroller circuitas further described herein which includes a circuit board that isfloating with respect to ground. An example of the microcontrollercircuit that may be included within the receiving system 150 is furtherdescribed with respect to FIG. 2.

FIG. 2 illustrates a microcontroller 200 for detecting AC and DC signalsfrom a phone line in accordance with an example embodiment. Referring toFIG. 2, the microcontroller 200 includes an electronic circuit board 205that is floating with reference to ground 270. In other words, theelectronic circuit board 205 may have a voltage passing through that isnot grounded to earth or via another circuit. The circuit board 205includes an input port 210 for receiving a telephone signal such as froma central office or another system or device. The circuit board 205 alsoincludes an output port 206 for outputting information detected from thephone signal (e.g., ringing voltage, caller ID, audio, etc.) to calltaking equipment such as a phone, a headset, a handset, a computingsystem, and the like. The microcontroller 200 may be embedded within atelephone, or it may be electronically coupled to the telephone in someway such as through cables, wires, or the like.

The microcontroller 200 further includes a processor 220 which maycontrol the overall operation of the other components of themicrocontroller 200. As a non-limiting example, the processor 220 mayinclude a field-programmable gate array (FPGA), an application-specificintegrated circuit (ASIC), or the like, but is not limited to aparticular type of processing device or circuit. The microcontrollerfurther includes a first A/D converter 230 and a second A/D converter240 for detecting DC and AC voltages, respectively, from the receivedtelephone signal. The microcontroller 200 also includes a power source250 which may be a DC power source or the like, and may be used tomaintain a 1500V in isolation between the line and the circuitry of thephone. Although not shown in FIG. 2, the microcontroller 200 may furtherinclude impedance matching circuitry to improve signal quality.

According to various aspects, the electronic circuit 205 is floatingwith reference to ground 270. The first A/D converter 230 may be coupledto the electronic circuit 205 and configured to detect ringing voltagesfrom DC voltages included in the telephone line. The second A/Dconverter 240 may be coupled to the electronic circuit 205 andconfigured to detect caller identification information from AC voltagesincluded in the telephone line. The processor 220 may be coupled to theelectronic circuit 205 and configured to control signals detected by thefirst and second A/D convertors 230 and 240 and output information aboutthe signals, via output port 260, to call taking equipment. In theexample of FIG. 2, the microcontroller 200 further includes the powersource 250 coupled to the electronic circuit 205 and configured tomaintain a voltage of 1500 volts in isolation between the telephone lineand the call taking equipment.

According to various aspects, the first A/D converter 230 may detecthigh voltage signals from the DC voltages while the second A/D converter240 may detect lower voltage signals from the AC voltages. In someembodiments, the first A/D converter 230 may further detect a polarityof a voltage indicating a state of the telephone line and DC signalingfrom the central office. In some embodiments, the second A/D converter240 may be further configured to detect audio transmitted during a phonecall and on-hook transmissions transmitted between calls. In someembodiments, the processor 220 may be further configured to output thedetected caller ID information to a display device of the call takingequipment. In some embodiments, although not shown specifically in FIG.2, the microcontroller 200 may further include a central processing unit(CPU), a memory, and a plurality of additional input/output ports forattaching to and receiving communications from other components anddevices.

To eliminate the issue of common mode rejection ratio (CMRR), themicrocontroller 200 can monitor AC voltages on the line whilemaintaining a very high CMRR. The circuit board 250 may also maintain a1500V isolation between the line side and the circuitry side towithstand any voltage surges that can occur on the telephone line. Themicrocontroller 200 is also small and low cost. In addition tomonitoring AC voltages, the microcontroller can monitor the DC voltageas well thereby providing a complete line monitoring solution. The powersource may generate a micro power microcontroller 200 using an isolatedDC power source. The microcontroller 200 is floating referenced toground and therefore presents a very good CMRR. The first A/D converter230 can monitor on a high voltage scale that will be used to measureringing voltages and DC voltages. Furthermore, the first A/D converter230 can detect a polarity of a battery voltage to indicate the state ofthe line and detect DC signaling from the central office. The second A/Dconverter 240 can small signals and may be used to measure the ACvoltages in the voice band for detection of the caller ID informationbut also the audio transmitted and received during a phone call orbetween calls (on-hook transmission).

Because of the requirement to be isolated from the telephone line at1500V, the circuitry that is connected to the telephone line must have agalvanic isolation from the rest of the telephone circuit. This meansthat the wall transformer powering the telephone circuit cannot powerthe isolated portion connected to the telephone line. In addition, anyactive circuitry (circuitry that requires power to operate) connected tothe telephone line requires a source of power that is also isolated at1500V to provide the required safety. For that reason, themicrocontroller cannot be part of the telephone line, it must be part ofthe telephone equipment. Meaning that it must be within the telephoneenclosure. The challenge is to power the microcontroller circuit whilemaintaining the product as small and compact as possible and maintainthe 1500V isolation at the same time. Not only that, but the audio andcontrol signals from the microcontroller must be transmitted to the “lowvoltage” side of the telephone circuit while maintaining the 1500Visolation.

The line side circuit has low power components that continually “listen”to the telephone line and digitize (render them digital) the AC and DCsignals to send them to the “low voltage” side of the telephoneequipment. This circuit includes the microcontroller itself, monitoringcircuits made of instrumentation amplifiers and anti-aliasing filtersmade with operational amplifiers. The microcontroller sends thedigitized signal serially over the isolation barrier toward the lowvoltage side.

The “circuitry side” is the “low voltage side” that is isolated from thetelephone line and safe. That portion of the circuit is made of a CPLD(Complex Programmable Logic Device) that takes the serial signal fromthe microcontroller and formats it so that it can be recognized andtreated by the processor and transformed back into voice or analyzed todetect call progress tones (e.g. dial tone, busy tone, ring back tone,etc.)

Common practice in the industry for the detection of caller IDinformation is to use either an isolation transformer or a DAA (DataAccess Arrangement). While the transformer solution provides a very goodCMRR, it is bulky and does not allow detection of the DC batterypresence and/or polarity. The DAA provides a small footprint, but itdoes not provide a battery polarity detection and the presence of DCbattery when on-hook. It also presents a lower CMRR that causes issuesin the presence of high levels of common mode signals.

By monitoring the DC voltage, the microcontroller herein can detect itspolarity, which is necessary for some functionalities, such as CAMA(Centralized Automatic Message Accounting), or E911 call takingapplications, where a battery reversal when off-hook means that theCentral Office (CO) is ready to receive tone signaling information andbattery reversal when on-hook means the CO trunk for that line is out ofservice. The microcontroller can also detect the presence or absence ofa DC battery. The absence of battery when on-hook means that the line isnot connected or in trouble, so we should not use it. The absence ofbattery when off-hook can be used by some CO for signaling purposes. TheAC detection in the on-hook state is used for caller ID transmission orfor on-hook transmission of data. The AC detection in the off-hook stateis used for the monitoring and/or recording of the emergency callwithout disturbing the call.

To meet UL requirements for call taking equipment, it must be groundedto the building ground. This causes detection problems when there arehigh levels of common mode signals on the telephone line. A circuit thatis floating referenced to ground is practically speaking completelyisolated from ground and the building ground has no effect or impact onthe signal being measured on the telephone line. A circuit that isfloating is usually rated at a certain voltage, meaning that if thedifference of potential (voltage) between that circuit and ground isincreased past that rating, the isolation is in danger of failing andcausing a conduction to ground.

FIG. 3 illustrates a method 300 for detecting AC and DC signals from atelephone line in accordance with an example embodiment. For example,the method 300 may be performed by a microcontroller (e.g.,microcontroller 200, etc.), a telephone, a computing system, acombination thereof, and/or the like. In 310, the method includesreceiving a telephone signal via a telephone line between call takingequipment and a central office. For example, the telephone signal mayinclude AC voltage and DC voltage that can be read by themicrocontroller. The telephone signal may be received via an input portof the microcontroller such as a phone line port, an ethernet port, acable port, and the like. The microcontroller (or other systemperforming the method) may be integrated within or otherwise coupled toa telephone system.

In 320, the method includes detecting, via a first A/D converter,ringing voltages from DC voltages included in the telephone signal, andin 330, the method includes detecting, via a second A/D converter,caller identification information from AC voltages included in thetelephone signal. Furthermore, in 340 the method includes controlling,via a processor, signals detected by the first and second A/D convertorsand outputting information about the signals to the call takingequipment. The components performing the method 300 such as the firstA/D converter, the second A/D converter, and the processor, may beelectronically connected to each other and coupled to an electroniccircuit that is floating with reference to ground.

Although not shown in FIG. 3, in some embodiments the method may furtherincluding maintaining a voltage of 1500 volts in isolation between thetelephone line and the call taking equipment. In some embodiments, themethod may further include detecting, via the first A/D converter, apolarity of a voltage from the telephone line indicating a state of thetelephone line and DC signaling from the central office. In someembodiments, the method may further include detecting, via the secondA/D converter, audio transmitted during a phone call, and outputting thedetected audio to the call taking equipment.

The above embodiments may be implemented in hardware, in a computerprogram executed by a processor, in firmware, or in a combination. Acomputer program may be embodied on a computer readable medium, such asa storage medium. For example, a computer program may reside in randomaccess memory (“RAM”), flash memory, read-only memory (“ROM”), erasableprogrammable read-only memory (“EPROM”), electrically erasableprogrammable read-only memory (“EEPROM”), registers, hard disk, aremovable disk, a compact disk read-only memory (“CD-ROM”), or any otherform of storage medium known in the art.

An exemplary storage medium may be coupled to the processor such thatthe processor may read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anapplication specific integrated circuit (“ASIC”). In the alternative,the processor and the storage medium may reside as discrete components.For example, FIG. 4 illustrates an example computer system architecture400, which may represent or be integrated in any of the above-describedcomponents, etc. The computer system 400 may be a single device or acombination of devices. For example, the computer system 400 may be acomputing system that executes one or more software applications for useby an emergency call taking position such as call-talking software,geographical mapping software, dispatching software, and the like, thatare used by emergency services for answering emergency calls. As oneexample, the computing system 400 may be included in the receivingsystem 150.

FIG. 4 is not intended to suggest any limitation as to the scope of useor functionality of embodiments of the application described herein.Regardless, the computing system 400 (or node 400) is capable of beingimplemented and/or performing any of the functionality set forthhereinabove.

In computing node 400 there is a computer system/server 402, which isoperational with numerous other general purpose or special purposecomputing system environments or configurations. Examples of well-knowncomputing systems, environments, and/or configurations that may besuitable for use with computer system/server 402 include, but are notlimited to, personal computer systems, server computer systems, thinclients, thick clients, hand-held or laptop devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network PCs, minicomputer systems, mainframecomputer systems, and distributed cloud computing environments thatinclude any of the above systems or devices, and the like.

Computer system/server 402 may be described in the general context ofcomputer system-executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 402 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 4, computer system/server 402 in computing node 400 isshown in the form of a general-purpose computing device. The componentsof computer system/server 402 may include, but are not limited to, oneor more processors or processing units 404 (i.e., processors), a systemmemory 406, and a bus that couples various system components includingsystem memory 406 to processor 404. The computing node 400 may be thecomputing system shown in the call taking station 150 of FIG. 1, acomputing system associated with a central office, or another device orcombination of devices such as a server, cloud platform, database,and/or the like.

The bus represents one or more of any of several types of busstructures, including a memory bus or memory controller, a peripheralbus, an accelerated graphics port, and a processor or local bus usingany of a variety of bus architectures. By way of example, and notlimitation, such architectures include Industry Standard Architecture(ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA)bus, Video Electronics Standards Association (VESA) local bus, andPeripheral Component Interconnects (PCI) bus.

Computer system/server 402 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 402, and it includes both volatileand non-volatile media, removable and non-removable media. System memory406, in one embodiment, implements the flow diagrams of the otherfigures. The system memory 406 can include computer system readablemedia in the form of volatile memory, such as random access memory (RAM)410 and/or cache memory 412. Computer system/server 402 may furtherinclude other removable/non-removable, volatile/non-volatile computersystem storage media. By way of example only, storage system 414 can beprovided for reading from and writing to a non-removable, non-volatilemagnetic media (not shown and typically called a “hard drive”). Althoughnot shown, a magnetic disk drive for reading from and writing to aremovable, non-volatile magnetic disk (e.g., a “floppy disk”), and anoptical disk drive for reading from or writing to a removable,non-volatile optical disk such as a CD-ROM, DVD-ROM or other opticalmedia can be provided. In such instances, each can be connected to thebus by one or more data media interfaces. As will be further depictedand described below, memory 406 may include at least one program producthaving a set (e.g., at least one) of program modules that are configuredto carry out the functions of various embodiments of the application.

Program/utility 416, having a set (at least one) of program modules 418,may be stored in memory 406 by way of example, and not limitation, aswell as an operating system, one or more application programs, otherprogram modules, and program data. Each of the operating system, one ormore application programs, other program modules, and program data orsome combination thereof, may include an implementation of a networkingenvironment. Program modules 418 generally carry out the functionsand/or methodologies of various embodiments of the application asdescribed herein. In some embodiments, the program modules 418 mayinclude software components for an emergency call taking position thatinteracts with telephone equipment used by an operator or otheremergency call taking user.

As will be appreciated by one skilled in the art, aspects of the presentapplication may be embodied as a system, method, or computer programproduct. Accordingly, aspects of the present application may take theform of an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present application may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Computer system/server 402 may also communicate with one or moreexternal devices 420 such as a keyboard, a pointing device, a display422, etc.; one or more devices that enable a user to interact withcomputer system/server 402; and/or any devices (e.g., network card,modem, etc.) that enable computer system/server 402 to communicate withone or more other computing devices. Such communication can occur viaI/O interfaces 424. Still yet, computer system/server 402 cancommunicate with one or more networks such as a local area network(LAN), a general wide area network (WAN), and/or a public network (e.g.,the Internet) via network adapter 426 (also referred to as a networkinterface). As depicted, network adapter 426 communicates with the othercomponents of computer system/server 402 via a bus. It should beunderstood that although not shown, other hardware and/or softwarecomponents could be used in conjunction with computer system/server 402.Examples, include, but are not limited to: microcode, device drivers,redundant processing units, external disk drive arrays, RAID systems,tape drives, and data archival storage systems, etc.

Although an exemplary embodiment of at least one of a system and methodhas been illustrated in the accompanied drawings and described in theforegoing detailed description, it will be understood that theapplication is not limited to the embodiments disclosed, but is capableof numerous rearrangements, modifications, and substitutions as setforth and defined by the following claims. For example, the capabilitiesof the system of the various figures can be performed by one or more ofthe modules or components described herein or in a distributedarchitecture and may include a transmitter, receiver or pair of both.For example, all or part of the functionality performed by theindividual modules, may be performed by one or more of these modules.Further, the functionality described herein may be performed at varioustimes and in relation to various events, internal or external to themodules or components. Also, the information sent between variousmodules can be sent between the modules via at least one of: a datanetwork, the Internet, a voice network, an Internet Protocol network, awireless device, a wired device and/or via plurality of protocols. Also,the messages sent or received by any of the modules may be sent orreceived directly and/or via one or more of the other modules.

One skilled in the art will appreciate that a “system” could be embodiedas a personal computer, a server, a console, a personal digitalassistant (PDA), a cell phone, a tablet computing device, a smartphoneor any other suitable computing device, or combination of devices.Presenting the above-described functions as being performed by a“system” is not intended to limit the scope of the present applicationin any way, but is intended to provide one example of many embodiments.Indeed, methods, systems and apparatuses disclosed herein may beimplemented in localized and distributed forms consistent with computingtechnology.

It should be noted that some of the system features described in thisspecification have been presented as modules, in order to moreparticularly emphasize their implementation independence. For example, amodule may be implemented as a hardware circuit comprising custom verylarge scale integration (VLSI) circuits or gate arrays, off-the-shelfsemiconductors such as logic chips, transistors, or other discretecomponents. A module may also be implemented in programmable hardwaredevices such as field programmable gate arrays, programmable arraylogic, programmable logic devices, graphics processing units, or thelike.

A module may also be at least partially implemented in software forexecution by various types of processors. An identified unit ofexecutable code may, for instance, comprise one or more physical orlogical blocks of computer instructions that may, for instance, beorganized as an object, procedure, or function. Nevertheless, theexecutables of an identified module need not be physically locatedtogether, but may comprise disparate instructions stored in differentlocations which, when joined logically together, comprise the module andachieve the stated purpose for the module. Further, modules may bestored on a computer-readable medium, which may be, for instance, a harddisk drive, flash device, random access memory (RAM), tape, or any othersuch medium used to store data.

Indeed, a module of executable code could be a single instruction, ormany instructions, and may even be distributed over several differentcode segments, among different programs, and across several memorydevices. Similarly, operational data may be identified and illustratedherein within modules, and may be embodied in any suitable form andorganized within any suitable type of data structure. The operationaldata may be collected as a single data set, or may be distributed overdifferent locations including over different storage devices, and mayexist, at least partially, merely as electronic signals on a system ornetwork.

It will be readily understood that the components of the application, asgenerally described and illustrated in the figures herein, may bearranged and designed in a wide variety of different configurations.Thus, the detailed description of the embodiments is not intended tolimit the scope of the application as claimed, but is merelyrepresentative of selected embodiments of the application.

One having ordinary skill in the art will readily understand that theabove may be practiced with steps in a different order, and/or withhardware elements in configurations that are different than those whichare disclosed. Therefore, although the application has been describedbased upon these preferred embodiments, it would be apparent to those ofskill in the art that certain modifications, variations, and alternativeconstructions would be apparent.

The invention claimed is:
 1. An alternating current and direct current(AC/DC) telephone line detection system, the system comprising: anelectronic circuit that is floating with reference to ground; a firstanalog-to-digital (A/D) converter coupled to the electronic circuit andconfigured to: detect ringing voltages from DC voltages carried by atelephone line, and detect a state of the telephone line based on apolarity of a DC signal from a battery; a second A/D converter coupledto the electronic circuit and configured to: detect calleridentification information from AC voltages carried by the telephoneline, the second A/D converter further configured to detect audiotransmitted during a phone call and on-hook transmissions transmittedbetween calls; and a processor configured to: output information aboutsignals detected by the first A/D converter and the second A/Dconverter.
 2. The AC/DC telephone line detection system of claim 1,further comprising: a power source coupled to the electronic circuit andconfigured to provide an isolation of 1500 volts minimum.
 3. The AC/DCtelephone line detection system of claim 2, wherein: the processor isconfigured to output the information about the signals to call takingequipment; and the power source is configured to provide an isolation of1500 volts between the telephone line and the call taking equipment. 4.The AC/DC telephone line detection system of claim 1, wherein the firstA/D converter is configured to: detect high voltage signals from the DCvoltages, the second A/D converter is configured to detect low voltagesignals from the AC voltages, and the high voltage signals have highervoltages than the low voltage signals.
 5. The AC/DC telephone linedetection system of claim 1, wherein the electronic circuit is includedin a microcontroller that includes a central processing unit, a memory,and a plurality of input/output ports that are embedded on theelectronic circuit.
 6. The AC/DC telephone line detection system ofclaim 1, wherein the first A/D converter is further configured to:detect a polarity of DC signaling from a central office (CO).
 7. TheAC/DC telephone line detection system of claim 1, wherein the processoris further configured to: output the detected caller ID information to adisplay device of the call taking equipment.
 8. A telephone system,comprising: a microcontroller configured to detect caller identification(ID) information from a telephone line being input to the telephonesystem and output the detected caller ID information to a display,wherein the microcontroller comprises: an electronic circuit that isfloating with reference to ground; a first analog-to-digital (A/D)converter coupled to the electronic circuit and configured to: detectringing voltages from DC voltages carried by a telephone line, anddetect a state of the telephone line based on a polarity of a DC signalfrom a battery; a second A/D converter coupled to the electronic circuitand configured to: detect caller identification information from ACvoltages carried by the telephone line, the second A/D converter furtherconfigured to detect audio transmitted during a phone call and on-hooktransmissions transmitted between calls; and a processor configured to:output information about signals detected by the first A/D c converterand the second A/D converter.
 9. The telephone system of claim 8,wherein the telephone system is included within a public-safety accesspoint (PSAP) for receiving emergency phone calls.
 10. The telephonesystem of claim 8, wherein the microcontroller further comprises: apower source coupled to the electronic circuit and configured to providean isolation of 1500 volts minimum.
 11. The telephone system of claim10, wherein: the processor is configured to output the information aboutthe signals to call taking equipment; and the power source is configuredto provide an isolation of 1500 volts between the telephone line and thecall taking equipment.
 12. The telephone system of claim 8, wherein: thefirst A/D converter is configured to detect high voltage signals fromthe DC voltages, the second A/D converter is configured to detect lowvoltage signals from the AC voltages, and the high voltage signals havehigher voltages than the low voltage signals.
 13. The telephone systemof claim 8, wherein the electronic circuit comprises: a centralprocessing unit, a memory, and a plurality of input/output ports. 14.The telephone system of claim 8, wherein the first A/D converter isfurther configured to: detect a polarity of DC signaling from a centraloffice (CO).
 15. A method, comprising: receiving a telephone signal viaa telephone line communicably coupled to a central office, the telephonesignal comprising alternating current (AC) and direct current (DC)voltages; detecting, via a first analog-to-digital (A/D) converter,ringing voltages from DC voltages of the telephone signal; detecting,via a first analog-to-digital (A/D) converter a state of the telephoneline based on a polarity of a DC signal from a battery; detecting, via asecond A/D converter, caller identification information from AC voltagesof the telephone signal; detecting, via the second A/D converter, audiotransmitted during a phone call and on-hook transmissions transmittedbetween calls; and controlling, via a processor, signals detected byfirst A/D converter and the second A/D converter, wherein the first A/Dconverter, the second A/D converter, and the processor, areelectronically connected to each other and coupled to an electroniccircuit that is floating with reference to ground.
 16. The method ofclaim 15, wherein the method further comprises: providing an isolationof 1500 volts minimum between the telephone line and call takingequipment.
 17. The method of claim 16, further comprising: detecting,via the second A/D converter, audio transmitted during a phone call, andoutputting the detected audio to the call taking equipment.
 18. Themethod of claim 15, further comprising: detecting, via the first A/Dconverter, a polarity of DC signaling from the central office.